55932Re: [softrock40] Re: Softrock sensitivity. [1 Attachment]
- Jun 2, 2011http://www.wb5rvz.com/sdr/sr_lite_ii/04_opamp.htmOn Wed, Jun 1, 2011 at 5:35 AM, Tony Parks <kb9yig@...> wrote:[Attachment(s) from Tony Parks included below]
The feedback resistors are supposed to be 4.99k resistors. The schematic page for the Lite II kit is included with this note.
On Wed, 2011-06-01 at 17:04 +0700, Martin Sole wrote:
Tony Parks kb9yig@... http://www.kb9yig.com
Okay, well I’m not convinced it’s working right yet. Here’s another thing I have just noted. In addition to the Lite I that am referring to I also have a TXRX 6.2 partially built for 20 and 30 metres. The receiver seems noticeably livelier. Connecting an antenna makes the noise jump up a good 10dB on 30 or 20 but has no obvious effect on the noise with the Lite II. About the only thing I can figure is a difference with the op-amp. The 6.2 and 6.3 have LT6231 op amps with 4.99k resistors in the feedback but the Lite II has the same LT6231 op-amp (changed from a TLV2462) but with 1k resistors in the feedback. It also has 1 resistors in the op –amp output. Just wondering about that.
From: email@example.com [mailto:firstname.lastname@example.org] On Behalf Of Alan
Sent: 01 June 2011 15:41
Subject: Re: [softrock40] Re: Softrock sensitivity.
----- Original Message -----
Subject: RE: [softrock40] Re: Softrock sensitivity.
> I'm still left with not being able to hear much below 1uV and that seems
> me to be about 20dB deafer than I would expect.
Sorry but I'm not familiar with how the figures compare with actual
If you search the messages you will find what others have said.
for example <http://groups.yahoo.com/group/softrock40/message/53438>
73 Alan G4ZFQ
--Cheers,RobbyRichard R. (Robby) RobsonAmateur Radio Station WB5RVZ
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